NEW YORK (CNN/Money) -
Energy markets rallied Monday, with crude futures gaining more than $4 a barrel, as a tropical storm threatened to move into the Gulf of Mexico as a hurricane and OPEC leaders voiced resistance to increasing crude output.

Surging markets in crude oil, natural gas, gasoline, and home heating oil catapulted contracts for October delivery to their biggest dollar gains ever, although in percentage terms the gains were not records.

U.S. light crude for October ended up $4.39 at $67.39 a barrel on the New York Mercantile Exchange, while natural gas futures rose $1.519, or about 13.6 percent, to a fresh record high of $12.663 per 1,000 cubic feet.

Home heating oil gained 11 percent to $2.0384 a gallon, and unleaded gasoline also soared 14.4 percent to $2.0427 a gallon on the NYMEX.

Energy analyst Fadel Gheit of Oppenheimer told CNN that what happens next in the energy markets all depends on the course of Tropical Storm Rita.

"We have not even recovered from Katrina, so it would be another big blow," Gheit said, referring to the possibility of another hurricane surging through the Gulf and disrupting oil production.

More than half the Gulf oil output is still shut down following Katrina.

Rita on the move

News that Rita was continuing to head west toward the already damaged Gulf Coast allowed the crude contract to recover all of Friday's $2-a-barrel drop and then some.

National Hurricane Center Director Max Mayfield told CNN that Rita could be a concern for the Gulf of Mexico and could threaten Texas and Louisiana within five days.

Phil Flynn, a senior energy analyst with Alaron Trading, said that fears sparked by the strengthening tropical storm are the main catalyst for the spike in the price of crude oil.

"This time it will be harder if we take another hit, and the market is accurately reflecting those fears," said Flynn. "We have to keep in mind that prices are well below crude prices" after Hurricane Katrina.

Three weeks ago, Katrina slammed into Louisiana, Mississippi and Alabama, damaging crude production and refining facilities and sending pipelines off-line for several days.

In response to Rita, several companies, including Chevron Corp., announced the evacuation of its workers stationed on its offshore oil and natural gas platforms in the Gulf of Mexico. The company said however that it would continue production in the meantime.

Analysts note that while crude prices have garnered the most attention, natural gas prices are especially vulnerable to price increases right now, since it is a difficult commodity to import and 20 to 25 percent of the U.S. supply comes from the Gulf of Mexico region.

"If you are in the market for natural gas, you will really have big issues here if it (Rita) shuts down production for any extended period of time," said Flynn.

Oil prices were also pushed higher as OPEC voiced its resistance to raising crude output. Beginning a two-day meeting Monday in Vienna, OPEC ministers said they were no longer in favor of raising crude output by 500,000 or 1 million barrels per day.

The cartel told Reuters Monday that it would however be willing to release 2 million bpd from spare capacity if the market demanded it.

"It's been the demand side more than the supply side keeping this market as firm as it has been, so when you start to get some data showing questions on the demand side ... it is going to take out some of that premium," ABN AMRO's John Brady told Reuters.